[mlir] Add `Block::eraseArguments` that erases a subrange

This patch adds a an `eraseArguments` function that erases a subrange of
a block's arguments. This can be used inplace of the terrible pattern

```
block->eraseArguments(llvm::to_vector(llvm::seq(...)));
```

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D132890